Named Entity Tagger

A Ruby library for tagging named entities in text based on OpenNPL. As OpenNLP is written in Java, NamedEntityTagger needs to be run on JRuby.

Dependencies

In order to use NamedEntityTagger, you need to download and build a few java libraries. The jar files need to be placed in the deps directory. Furthermore, you need OpenNLP model data that must be placed under models.

Libraries

• OpenNLP Tools
• OpenNLP Maxent
• GNU Trove

Model Data

• Sentence Detection
• Dates
• Locations
• Oranizations
• Persons

Usage

NamedEntityTagger exposes a minimal API. The main class is EntityTagger and it provides the method #tag(text). This method takes the text that should be tagged and returns a new string where the words that were identified as named entities are highlighted. The encoding of the output is defined by a formatter object. Currently there is only the CSSClassAnnotationFormatter that adds span tags around the named entities. The span tag has a class corresponding to the model that matched the entity.

For example:

require 'lib/entity_tagger'
require 'lib/css_class_annotation_formatter' 
tagger = EntityTagger.new(CSSClassAnnotationFormatter.new)
tagger.tag("Mrs. Smith flew to Berlin")

=> "Mrs. <span class="person">Smith</span> flew to <span class="location">Berlin</span>"